KTP
was first introduced as the NLO crystal for Nd doped laser systems
with high conversion efficiency. Under certain conditions, the conversion
efficiency was reported to 80%, which leaves other NLO crystals far behind.

Recently,
with the development of laser diodes, KTP is widely used as SHG
devices in diode pumped Nd:YVO4 solid laser
systems to output green laser, and also to make the laser system very compact.

KTP
for OPA, OPO Applications:

In
addition to its wide use as a frequency doubling device in Nd-doped
laser systems for Green/Red output, KTP is also one of the most
important crystals in parametric sources for tunable output from
visible (600nm) to mid-IR (4500nm) due to the popularity of its
pumped sources, the fundamental and second harmonic of a Nd:YAG
or Nd:YLF lasers.

One
of the most useful applications is the non-critical phase-matched
(NCPM) KTP OPO/OPA pumped by the tunable lasers to obtain a high
conversion efficiency.

KTP
OPO results in stable continuous outputs of femto-second pulse of
108 Hz repetition rate and milli-watt average power levels in both
signal and idler outputs.